I have to say I love my food chopper. However, I do find that there are certain things that this is absolutely NOT made for. Like for instance, goat cheese... it just gobbs up in there and gets stuck. I know that the blades dont seem to be very sharp, and according to other posts , there is not sharperner available. What works best to demonstrate this? I mostly use it for onions and tomatoes, but sometimes even with the skin facing up, the chopping doesnt come out so well. (like there are lots of large chunks that are cut, but not all the way through) I am really good with the knife, but the food chopper just seems so much more practical for people who dont like to use the knife for chopping. So basically my question is , what food is best/worst to demonstrate the chopper?